Russian President Vladimir Putin has offered his thoughts on Ukraine, the Winter Olympics, a prison amnesty, Iran's nuclear program, and Edward Snowden, among other issues, during a marathon four-hour press conference,

Putin, who offered Ukraine $15 billion in credits and slashed one-third off the price Ukraine pays for vital Russian natural-gas supplies earlier this week, said the deals were reached "taking the Ukrainian people's interests into account" and had nothing to do with Ukraine's moves toward an Association Agreement with the EU.

"You know, I'll be completely serious and free of any irony -- we often exploit the term of 'brotherly country' or 'brotherly nation,'" he said while speaking to to more than 1,000 Russian and foreign journalists on December 19.

"Today, we see that Ukraine is in a complicated economic, political, and social situation. This situation has emerged due to a number of circumstances and reasons, but nevertheless it is objective," he continued.

"If we are serious calling [Ukraine] our brotherly country, then we ought to behave as close relatives and support the Ukrainian people in this complex situation. I assure you that this is the absolutely main reason why we made this decision."

He said Russia had not asked for anything in return.

Response To Missile Defense

Putin also commented on reports of the deployment of Iskander short-range missiles in Russia's westernmost Baltic exclave of Kaliningrad.

"A new and very important segment of American strategic weapons is being installed on the periphery of Europe -- a missile-defense system. We have said many times that this system constitutes a threat to our nuclear capacity, and we will be compelled to react to it one way or the other," he said.

"I believe even my predecessor used to say that one of the ways of our reaction would be the deployment of the Iskander [missile] system in the Kaliningrad region. There is nothing new in this."

Putin urged calm over the situation, though, saying that the Kremlin had not yet decided whether to deploy the nuclear-capable missiles in Kaliningrad.

NSA 'Fighting Terrorism'

Putin also said that fugitive former U.S. intelligence contractor Edward Snowden, who has been granted temporary asylum in Russia, had embarked on a "noble cause" but that his path looked "very challenging."

Putin defended the work of the U.S. National Security Agency (NSA), however, saying it was necessary in today's world.

"As much as our American friends are being scolded now, initially -- and I believe it continues to be so today -- all of this [intelligence] work is being done primarily to fight terrorism," he said.

Putin added, however, that the U.S. government must "limit the appetite" of the agency with a clear set of ground rules.

Sochi, Iran

Speaking of the upcoming Winter Olympics in Sochi, Putin vowed to ensure equal conditions for all athletes at the February games.

A law signed earlier this year in Russia bans the distribution of "propaganda" to minors about nontraditional sexual relationships.

The law has raised wide concern about whether gay athletes and spectators would face discrimination at the Olympics.

On Iran, Putin praised the role of the United States in forging an interim deal to ease concerns about its suspect nuclear program, but said any talk of further tightening sanctions would be a "counterproductive decision."

He also expressed hope that the case of the 30 Greenpeace activists arrested over a protest in September at an Arctic oil platform will serve as a "lesson for anyone who wants to do the same."